1. Field of the Invention
The present invention relates to an external combustion engine using evaporation and condensation of a working fluid to cause a liquid phase part of the working fluid to displace, and converting the displacement of the liquid phase part of the working fluid to mechanical energy for output.
2. Description of the Related Art
In the past, one external combustion engine was disclosed in Japanese Patent Publication (A) No. 2005-330885. In such an external combustion engine, a container in which a working fluid is sealed flowable in the liquid phase state, is formed with a heating portion heating part of the liquid phase state working fluid to evaporate it, and a cooling portion cooling the working fluid evaporated at the heating portion to condense it.
By alternately repeating this evaporation and condensation of the working fluid, the liquid phase part of the working fluid is made to cyclically displace, and the vibration of the liquid phase part of the working fluid is taken out at the output part as mechanical energy.
In the prior art, the part of the container at the output part side is formed by a single merging pipe and the parts of the container forming the heating portion and cooling portion are formed by large numbers of branch pipes so as to increase the heat conduction areas of the heating portion and cooling portion. Due to this, the heating efficiency (evaporation efficiency) and cooling efficiency (condensation efficiency) of the working fluid are improved to increase the output of the external combustion engine.
In the above prior art, when the liquid phase state working fluid did not sufficiently reach the heating portion, the heating efficiency (evaporation efficiency) of the working fluid could fall and in turn the output of the external combustion engine could fall.
In the above prior art, the part of the container at the output part side was formed by a single merging pipe, while the parts of the container forming the heating portion and cooling portion were formed by large numbers of branch pipes. According to detailed studies of the inventors, branch pipes where the liquid phase state working fluid will easily reach the heating portion and branch pipes where the liquid phase state working fluid will have a hard time reaching the heating portion end up being formed and, as a result, the output of the external combustion engine can be lowered. Such a state occurs not only when there are large numbers of branch pipes, but also when there are two branch pipes.